Title: Hormonal control of gene expression in the ovary.

POPLINE Document Number: 075745

Author(s):

Richards JS

Source citation:

In: Growth factors in fertility regulation. Proceedings of the Symposium on Potential of Molecular Biology in Fertility Regulation: Growth Regulatory Factors, jointly sponsored by the World Health Organization and the National Institute of Child Health and Human Development and held at the National Institutes of Health, Bethesda, Maryland, on September 22-24, 1988, edited by Florence P. Haseltine, Jock K. Findlay. Cambridge, England, Cambridge University Press, 1991. :79-98. (Scientific Basis of Fertility Regulation)

Abstract:

The following genes were analyzed: RII-beta, the regulatory subunit of cyclic adenosine monophosphate (cAMP)-dependent protein kinase type II, aromatase cytochrome P450 (P450-arom) cholesterol side-chain cleavage cytochrome P450 (P450-scc), 17-alfa-hydroxylase cytochrome P450 (P450-17alfa) and prostaglandin endoperoxide synthase (PGS). Results showed that the levels of mRNA and enzyme for P450-17-alfa, P450-SCC and P450-arom increase during the development of preovulatory follicles in response to follicle stimulating hormone (FSH), to low but increasing concentrations of luteinizing hormone LH (cAMP), and to estradiol. The LH surge and elevated concentrations of cAMP terminate follicular growth and stimulate distinct changes in the expression of each gene. P450-17-alfa is repressed, P450-SCC is markedly induced, the amount of P450-arom declines transiently and is subsequently increased by the action of the hormones, rat placental lactogen (rPL) and testosterone (or estradiol). These results support the hypothesis that the transformation of a preovulatory follicle to a corpus luteum involves a shift from cAMP-dependent regulation of cell function to cAMP-independent mechanisms which affect other signal-transduction pathways. The molecular basis of diverse mechanisms that regulate levels of PGS and the P450 enzymes during differentiation of ovarian cells is not yet determined. Nevertheless, these changes suggest that there are tissue- and hormone-specific domains that regulate the transcription of each gene. Each gene also seems to have one or more cAMP regulatory elements (CRE). One CRE responds to low concentrations of cAMP and acts to increase the rate of transcription of each gene during follicular development. On the other hand, other CRE domains, presumably interacting with distinct cAMP-regulated transcription factors, are altered only as a result of elevated intracellular concentrations of cAMP.

Keywords:

Genetic Technics
Ovarian Effects
Adenosine Cyclic Monophosphate
Follicle Stimulating Hormone
Luteinizing Hormone
Cytologic Effects
Corpus Luteum
Prostaglandins
Laboratory Examinations and Diagnoses
Examinations and Diagnoses
Ovary
Genitalia, Female
Genitalia
Urogenital System
Physiology
Biology
Gonadotropins, Pituitary
Gonadotropins
Hormones
Endocrine System